They may be. Water under a kitchen sink usually soaks the cabinet floor first, then runs under the cabinet base and into the subfloor, the hardwood in front of the cabinets or the ceiling below, where you can't see it. A moisture reading around the cabinet and the flooring next to it shows how far it went.
Under-sink leaks are often slow, and the cabinet is full of things that hide the water. Here's how to find the source, what damage to look for and when the cabinet and floor can be dried.
Where Is the Leak Coming From?
Empty the cabinet, dry everything, and put a dry paper towel on the cabinet floor. Run the faucet, then the disposal, then the dishwasher, and see where water shows up.
Supply lines and shutoff valves: drips or a steady leak even when nothing is running.
Faucet connections: water when the faucet is on, often running down the lines.
The drain trap and slip nuts: water when the sink drains.
Garbage disposal: leaks from the body or the connections when it runs.
Dishwasher drain or supply connections: water during a cycle.
Filter systems or an ice maker line tee: water around the fitting or housing.
A plumber can fix the source. If you can't find it, shut off the valves under the sink, or the main shutoff, until they arrive.
What Are the Signs of Damage?
A cabinet floor that's swollen, soft, stained or delaminating
Warped toe kicks or cabinet sides
Hardwood in front of the sink that's cupping, darkened or has gaps
Vinyl or laminate that's lifting at the seams
A stain or drip on the ceiling below, if the kitchen is above a basement or another room
A musty smell when you open the cabinet doors
The cabinet floor can look fine while water sits under it. A moisture reading tells the real answer. We check the cabinet base, the toe kick area, the flooring in front of and beside the cabinet, and the ceiling below with meters.
What Should I Do Right Now?
Shut off the water at the valves under the sink or the main shutoff.
Empty the cabinet and dry what you can reach.
Leave the doors open so air can move into the cabinet.
Take photos of the leak, the cabinet floor and any floor or ceiling damage.
Call a plumber for the repair, and call us if water reached the flooring, the toe kick or the ceiling below.
Water under your sink reached the floor? Call Blue Valley at (913) 395-8488. Open 7 AM–9 PM, every day.
Can the Cabinet and Floor Be Saved?
Often, depending on the materials and how long they were wet. Plywood cabinet bases tend to dry better than particleboard, which can swell and lose strength once soaked. Hardwood in front of the sink sometimes responds to drying mats that pull moisture up through the boards. When drying makes sense, we may remove the toe kick and drill small holes in the cabinet base so air can reach the space underneath, then set air movers and a dehumidifier. Our hardwood floor water damage page explains floor drying, and can wet hardwood floors be saved covers that decision.
Does Insurance Cover a Leak Under the Sink?
It depends on your policy and the cause. A supply line that suddenly breaks is often treated differently from a slow drip that went on for months, which many policies exclude. Ask your agent. We document the damage and the drying with photos and moisture readings to help with the claim.
Shawnee and Nearby Homes
In many homes the kitchen sits above a basement or another room, so an under-sink leak can show up as a ceiling stain downstairs. We dry sink cabinets, floors and ceilings after kitchen leaks in Shawnee, Overland Park, Leawood and nearby cities. The dishwasher usually shares the sink cabinet's plumbing, too, so leaks from both often look alike. If the dishwasher or refrigerator might be the source, see refrigerator or dishwasher leak in the kitchen and our appliance leak cleanup page.
Frequently Asked Questions
Can I just replace the cabinet floor with a new panel?
Not until the space under it is dry. Covering wet subfloor can trap moisture and lead to odors and more damage later.
How long does it take to dry under a sink cabinet?
It depends on how long it was wet and what the cabinet and floor are made of. We track readings until they match dry areas of the kitchen.
Will my countertops have to come off?
Usually not. In most cases the base cabinet can be dried in place. If a cabinet has to be replaced, the countertop may need to be lifted, and we'll explain that before anything is removed.
Should I keep using the sink?
Not until the leak is repaired. Even a small drip keeps adding water under the cabinet.
Call our restoration team
If a leak under your sink soaked the cabinet or floor, call Blue Valley at (913) 395-8488. Open 7 AM–9 PM, every day. We're IICRC Certified & Fully Insured. We'll check the cabinet and floor with a moisture meter and give you a free evaluation. Read about our water damage restoration in Shawnee.